Rotationally-hindered furyl fulgides

Fulgides are a representative class of photochromic organic mol­ecules which exhibit several inter­esting properties for diverse applications in fields such as data storage or high-resolution spectroscopy. The crystal structures of three furyl fulgides with different steric constraints were determined and for two of the compounds both the E and Z isomer structures were defined. The compounds are 3-[(E)-1,3-dimethyl-4,5,6,7-tetra­hydro-2-benzofuran-4-yl­idene]-4-isopropyl­idene­tetra­hydro­furan-2,5-dione, C₁₇H₁₈O₄, (I-E), 3-[(E)-1,3-dimethyl-5,6,7,8-tetra­hydro-4H-cyclo­hepta­[c]furan-4-yl­idene]-4-iso­pro­pyl­idene­tetra­hydro­furan-2,5-dione, C₁₈H₂₀O₄, (II-E), and the Z isomer, (II-Z), and 3-isopropyl­idene-4-[(E)-1-(5-meth­oxy-2-methyl-1-benzofuran-3-yl)ethyl­idene]tetra­hydro­furan-2,5-di­one, C₁₉H₁₈O₅, (III-E), with two molecules in the asymmetric unit, and the Z isomer, (III-Z). The structures of the E and Z isomers show only little differences in the bond lengths and angles inside the hexa­triene unit. Because of the strained geometry there are deviations in the torsion angles. Furthermore, small differences in the distances between the bond-forming C atoms in the electro­cyclization process give no explanation for the unequal photochromic behaviour.

S1. Comment

Among photochromic compounds furyl fulgides exhibit suitable properties with a high application potential (Yokoyama, 2000). Upon wavelength-specific illumination they undergo a remarkable reversible colour change, which can be followed by UV/visible spectroscopy. The photochromic reaction occurs by a photochemical ring-closing reaction of a hexatriene system and can be reversed by irradiation with light of a different wavelength. Concomitantly there is a photochemical equilibrium between the open E and Z forms. The reaction scheme below illustrates the photochromism of a furyl fulgide with variable substituents at the hexatriene moiety. One great advantage of fulgides compared with other photochromic compounds is the high thermal stability, which is due to structural modifications at the hexatriene part. This was intensively investigated by Heller et al. in the 1980 s (Darcy et al., 1981). Furthermore, electronic variations show a great influence on the UV/visible spectroscopic characteristics of a fulgide (Yokoyama et al., 1991, 1996). Steric modifications at the hexatriene unit show strong effects on the quantum yields, which correspond with the effectiveness of the photochromic reaction. Bulky substituents reduce the E–Z isomerization in favour of the E–C ring closure and increase the quantum yield of the latter (Yokoyama et al., 1988; Kiji et al., 1995). Because of the single bond connection between the heterocyclic part and the anhydride moiety a rotation process is possible. This process of diastereotopomerization results in an equilibrium of the (P)-E_α and (M)-E_β conformation. With the synthesis of a series of rotation-hindered fulgides, we improve the efficiency of the photochromic reaction. This is achieved by limiting unfavourable reactions, which compete with the ring closure from the E to the C isomer. In a comparative study we analysed three furyl fulgides with different steric constraints to their furyl backbone. Fulgides (I) and (II) contain a bridging alkyl chain between the hexatriene and the furyl moieties. Therefore the rotation around the C_b—C_c bond is unfeasible and no E_α–E_β diastereotopomerization occurs. For fulgide (III) the rotation should be limited to a minimal amount because of benzoannulation to the furyl part. By limiting the rotation all or at least most of the photochromic molecules are available in the correct geometric conformation for cyclization. The effects of the structural modifications were investigated by UV/visible and femtosecond time-resolved transient absorption spectroscopy (Siewertsen et al., 2011; Strübe et al., 2011).

Herein we present the molecular structures of furyl fulgides (I)–(III) in the crystalline state and the detailed analysis of the bond lengths, bond angles and selected torsion angles of the hexatriene unit of each fulgide. In addition, we analysed the distances between the two bond-forming carbon atoms C_a and C_f. The structures of compounds (I)–(III) are depicted in Fig. 1. In the crystalline state the E isomers of (I)–(III) take the helical (P)-E_α conformation. This is due to the steric repulsion of the methyl groups at C_a and C_f. For (III-E) the unit cell contains two forms [(III-Ea) and (III-Eb)] with slightly different parameters owing to packing effects. Table 1 shows selected bond lengths and angles and torsion angles for the hexatriene systems of each fulgide. As expected for all structures the bond lengths inside the hexatriene unit alternate between short and long corresponding to the alternating single and double bonds. The fulgides (I)–(III) do not differ significantly with respect to bond distances and angles. These results are in agreement with previously published structures of indolyl fulgides (Wolak et al., 2002). Furthermore, the atom distances between C_a and C_f are in the same range as for the indolyl fulgides. Hence, these values can give no explanation for the different photochromic properties. Because of the strained geometry the torsion angles for fulgide (I-E) show deviations from the other compounds. At least no trend can be observed, which correlates with the photochemical observations for the E forms. The Z isomers of (II) and (III) have almost equal properties with regard to the bond lengths and angles. Discrepancies up to 15° are observed for the torsion angles. As there is no possibility for direct Z–C cyclization it is not useful to make any suggestions for the correlation between the photochemical and structural properties. In summary, the small variations in the crystallographic structures give no explanation for the different photochromic behaviour.

Related literature

For related literature, see: Darcy et al. (1981); Kiji et al. (1995); Siewertsen et al. (2011); Strübe et al. (2011); Wolak et al. (2002); Yokoyama (2000); Yokoyama et al. (1988, 1991, 1996).

S2. Experimental

Fulgides (I)–(III) were synthesized following the principles of the Stobbe condensation (Strübe et al., 2011). The condensation was performed using lithium diisopropylamide in tetrahydrofuran (THF) at 195 K followed by saponification with an aqueous solution of potassium hydroxide in ethanol at 343 K. For dehydration, N,N'-dicyclohexylcarbodiimide was used. Fulgides (I-E) and (III-E) were recrystallized from diethyl ether, fulgide (II) was recrystallized from cyclohexane and the (III-Z) isomer was recrystallized from ethanol. Spectroscopic data for all compounds are available in the archived CIF,

S3. Refinement

H atoms were placed in geometric positions and refined as riding, with C—H = 0.95–0.98 Å and U_iso(H) = 1.2U_eq(C).

Computing details

For all compounds, data collection: COLLECT (Bruker, 2004); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL-Plus (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

Fig. 1. The molecular structures of fulgides (I)–(III). H atoms have been omitted for clarity. The unit cell of (III-E) contains two forms, viz. (III-Ea) and (III-Eb). For each structure, the displacement ellipsoids are drawn at the 50% probability level.

(I-E) 3-[(E)-1,3-dimethyl-4,5,6,7-tetrahydro-2-benzofuran-4-ylidene]-4- isopropylidenetetrahydrofuran-2,5-dione

Crystal data

C17H18O4	F(000) = 608
Mr = 286.31	Dx = 1.329 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 40527 reflections
a = 8.7142 (2) Å	θ = 2.9–27.5°
b = 12.0207 (3) Å	µ = 0.09 mm^−1
c = 13.9102 (4) Å	T = 100 K
β = 100.9737 (18)°	Block, light yellow
V = 1430.46 (6) Å^3	0.27 × 0.12 × 0.10 mm
Z = 4

Data collection

KappaCCD diffractometer	3278 independent reflections
Radiation source: fine-focus sealed tube	2810 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.044
CCD scans	θmax = 27.5°, θmin = 2.9°
Absorption correction: multi-scan (DENZO and SCALEPACK; Otwinowski & Minor, 1997)	h = −11→11
Tmin = 0.975, Tmax = 0.991	k = −15→15
33163 measured reflections	l = −18→18

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.099	H-atom parameters constrained
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0526P)^2 + 0.3631P] where P = (Fo^2 + 2Fc^2)/3
3278 reflections	(Δ/σ)max < 0.001
194 parameters	Δρmax = 0.26 e Å^−3
0 restraints	Δρmin = −0.21 e Å^−3

Special details

Experimental. General preparation of fulgides (I)–(III): a solution of diethyl isopropylidene succinate (15 mmol) in THF [tetrahydrofuran?] (15 ml) was cooled to 195 K and LDA (7.5 ml, 15 mmol; 2 M, THF/n-heptane/ethylbenzene) was added under an argon atmosphere. After stirring for 1 h the appropriate ketone (10 mmol) dissolved in THF (30 ml) was added via a syringe. The reaction mixture was allowed to warm to room temperature overnight and stirred for an additional 24 h. The reaction progress was monitored by TLC [thin layer chromatography?]. Afterwards the reaction mixture was acidified with aqueous HCl (2 M) and the aqueous layer was extracted with ethyl acetate (3 x 50 ml). The combined organic layers were washed with saturated aqueous NaCl solution, dried over MgSO₄ and the solvent was removed in vacuo. The residue was dissolved in cyclohexane/ethyl acetate (7:3), filtered over silica gel and the solvent removed in vacuo again. The residue was dissolved in ethanol (60 ml) and a saturated aqueous solution of KOH (5 ml) was added. After stirring for 20 h at 343 K the reaction mixture was poured onto ice and acidified with aqueous HCl (2 M). The aqueous layer was extracted with ethyl acetate (3 x 50 ml) and the combined organic layers were washed with saturated aqueous NaCl, dried over MgSO₄ and the solvent was removed in vacuo. The dark brown residue was dissolved in dichloromethane (50 ml) and N,N'-dicyclohexylcarbodiimide (4.13 g, 20 mmol) was added. After stirring for 48 h the reaction mixture was filtered over silica gel and the solvent was removed in vacuo. The products were purified by column chromatography and recrystallized from adapted solvents.

(I-E): yield 6% (recrystallized from diethyl ether); R_f=0.34 (cyclohexane/ethyl acetate 9:1); ¹H NMR (500 MHz, CDCl₃, 25 °C, CDCl₃=7.24 p.p.m.) δ=1.29 (s, 3H; CH₃), 1.71–1.80 (m, 1H; CH₂), 1.76 (s, 3H; CH₃), 1.96–2.03 (m, 1H; CH₂), 2.16 (s, 3H; CH₃), 2.43 (s, 3H; CH₃), 2.46 (m, 1H; CH₂), 2.49–2.59 (m, 2H; CH₂), 3.81 p.p.m. (m, 1H; CH₂); ¹³C NMR (126 MHz, CDCl₃, 25 °C, CDCl₃=77.0 p.p.m.) δ=11.4, 15.8, 19.7, 22.4, 24.6, 27.1, 30.5, 114.2, 117.1, 121.6, 122.1, 144.9, 149.3, 149.5, 151.2, 163.5, 164.2 p.p.m.; MS (70 eV): m/z (%): 287 (20), 286 (100) [M⁺], 271 (15) [M - CH₃⁺], 243 (40), 213 (18), 199 (23), 197 (17), 128 (17), 115 (16), 43 (96); HRMS (m/z) [M⁺] calcd for C₁₇H₁₈O₄: 286.11996; found 286.12060.

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.17048 (11)	0.60212 (7)	0.43493 (7)	0.0341 (2)
O2	0.12908 (9)	0.59003 (7)	0.58849 (6)	0.0266 (2)
O3	0.11630 (10)	0.53979 (7)	0.74171 (6)	0.0309 (2)
O4	0.21962 (9)	0.06363 (6)	0.50423 (5)	0.02193 (18)
C1	0.18781 (13)	0.54803 (10)	0.50866 (8)	0.0243 (2)
C2	0.25216 (12)	0.43615 (9)	0.53530 (8)	0.0208 (2)
C3	0.26082 (12)	0.42624 (9)	0.64167 (8)	0.0204 (2)
C4	0.16289 (12)	0.51753 (9)	0.66828 (8)	0.0237 (2)
C5	0.36521 (12)	0.36950 (9)	0.70866 (8)	0.0214 (2)
C6	0.48904 (13)	0.29856 (10)	0.67894 (8)	0.0245 (2)
H6A	0.4536	0.2211	0.6730	0.037*
H6B	0.5851	0.3038	0.7285	0.037*
H6C	0.5096	0.3243	0.6158	0.037*
C7	0.37237 (14)	0.37549 (10)	0.81720 (8)	0.0269 (3)
H7A	0.2874	0.4228	0.8308	0.040*
H7B	0.4730	0.4070	0.8489	0.040*
H7C	0.3613	0.3006	0.8428	0.040*
C8	0.27311 (12)	0.36091 (9)	0.46513 (8)	0.0209 (2)
C9	0.30105 (14)	0.39744 (10)	0.36569 (8)	0.0264 (3)
H9A	0.3155	0.4791	0.3648	0.032*
H9B	0.2098	0.3777	0.3145	0.032*
C10	0.44906 (14)	0.33828 (11)	0.34531 (9)	0.0287 (3)
H10A	0.4773	0.3699	0.2853	0.034*
H10B	0.5370	0.3526	0.4004	0.034*
C11	0.42584 (13)	0.21292 (11)	0.33238 (8)	0.0269 (3)
H11A	0.3652	0.1968	0.2662	0.032*
H11B	0.5287	0.1757	0.3391	0.032*
C12	0.33982 (12)	0.16915 (10)	0.40873 (8)	0.0218 (2)
C13	0.27329 (12)	0.24068 (9)	0.47418 (7)	0.0203 (2)
C14	0.19929 (12)	0.17166 (9)	0.52943 (8)	0.0206 (2)
C15	0.30638 (12)	0.06369 (10)	0.43030 (8)	0.0223 (2)
C16	0.09632 (13)	0.18821 (9)	0.60192 (8)	0.0240 (2)
H16A	0.0246	0.1250	0.5992	0.036*
H16B	0.0360	0.2569	0.5866	0.036*
H16C	0.1604	0.1936	0.6678	0.036*
C17	0.34399 (14)	−0.04732 (10)	0.39439 (9)	0.0276 (3)
H17A	0.4130	−0.0385	0.3469	0.041*
H17B	0.2473	−0.0844	0.3628	0.041*
H17C	0.3965	−0.0924	0.4497	0.041*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0386 (5)	0.0286 (5)	0.0335 (5)	0.0061 (4)	0.0033 (4)	0.0097 (4)
O2	0.0250 (4)	0.0217 (4)	0.0325 (5)	0.0043 (3)	0.0041 (3)	−0.0006 (3)
O3	0.0303 (4)	0.0319 (5)	0.0319 (5)	0.0039 (3)	0.0094 (4)	−0.0083 (4)
O4	0.0244 (4)	0.0215 (4)	0.0202 (4)	0.0018 (3)	0.0052 (3)	−0.0017 (3)
C1	0.0207 (5)	0.0227 (6)	0.0281 (6)	−0.0005 (4)	0.0012 (4)	−0.0013 (4)
C2	0.0184 (5)	0.0215 (5)	0.0219 (5)	−0.0003 (4)	0.0024 (4)	0.0012 (4)
C3	0.0193 (5)	0.0206 (5)	0.0216 (5)	−0.0013 (4)	0.0047 (4)	−0.0031 (4)
C4	0.0197 (5)	0.0222 (5)	0.0280 (6)	−0.0012 (4)	0.0018 (4)	−0.0035 (4)
C5	0.0223 (5)	0.0193 (5)	0.0225 (5)	−0.0030 (4)	0.0042 (4)	−0.0024 (4)
C6	0.0227 (5)	0.0248 (6)	0.0248 (5)	0.0023 (4)	0.0015 (4)	0.0001 (4)
C7	0.0312 (6)	0.0282 (6)	0.0203 (5)	−0.0002 (5)	0.0023 (4)	−0.0016 (4)
C8	0.0178 (5)	0.0244 (6)	0.0199 (5)	−0.0002 (4)	0.0021 (4)	0.0014 (4)
C9	0.0313 (6)	0.0276 (6)	0.0202 (5)	−0.0026 (5)	0.0049 (4)	0.0023 (4)
C10	0.0283 (6)	0.0369 (7)	0.0225 (6)	−0.0072 (5)	0.0088 (4)	−0.0010 (5)
C11	0.0235 (5)	0.0357 (7)	0.0228 (5)	−0.0007 (5)	0.0073 (4)	−0.0031 (5)
C12	0.0185 (5)	0.0279 (6)	0.0187 (5)	0.0013 (4)	0.0024 (4)	−0.0024 (4)
C13	0.0189 (5)	0.0241 (6)	0.0174 (5)	0.0004 (4)	0.0021 (4)	−0.0018 (4)
C14	0.0216 (5)	0.0204 (5)	0.0190 (5)	0.0021 (4)	0.0018 (4)	−0.0016 (4)
C15	0.0194 (5)	0.0289 (6)	0.0183 (5)	0.0021 (4)	0.0025 (4)	−0.0037 (4)
C16	0.0266 (5)	0.0228 (6)	0.0245 (5)	−0.0002 (4)	0.0096 (4)	0.0002 (4)
C17	0.0286 (6)	0.0283 (6)	0.0255 (6)	0.0028 (5)	0.0041 (5)	−0.0072 (5)

Geometric parameters (Å, º)

O1—C1	1.1993 (15)	C8—C9	1.5145 (15)
O2—C4	1.3977 (14)	C9—C10	1.5456 (17)
O2—C1	1.4023 (14)	C9—H9A	0.9900
O3—C4	1.1990 (14)	C9—H9B	0.9900
O4—C14	1.3654 (13)	C10—C11	1.5265 (18)
O4—C15	1.3875 (13)	C10—H10A	0.9900
C1—C2	1.4769 (15)	C10—H10B	0.9900
C2—C8	1.3682 (15)	C11—C12	1.5066 (15)
C2—C3	1.4721 (15)	C11—H11A	0.9900
C3—C5	1.3559 (15)	C11—H11B	0.9900
C3—C4	1.4797 (15)	C12—C15	1.3473 (17)
C5—C6	1.4940 (15)	C12—C13	1.4510 (15)
C5—C7	1.5008 (15)	C13—C14	1.3725 (15)
C5—C14	3.5482 (15)	C14—C16	1.4852 (15)
C6—H6A	0.9800	C15—C17	1.4832 (16)
C6—H6B	0.9800	C16—H16A	0.9800
C6—H6C	0.9800	C16—H16B	0.9800
C7—H7A	0.9800	C16—H16C	0.9800
C7—H7B	0.9800	C17—H17A	0.9800
C7—H7C	0.9800	C17—H17B	0.9800
C8—C13	1.4507 (16)	C17—H17C	0.9800
C4—O2—C1	110.54 (9)	H9A—C9—H9B	108.4
C14—O4—C15	107.79 (8)	C11—C10—C9	112.29 (9)
O1—C1—O2	118.46 (10)	C11—C10—H10A	109.1
O1—C1—C2	133.49 (11)	C9—C10—H10A	109.1
O2—C1—C2	107.91 (9)	C11—C10—H10B	109.1
C8—C2—C3	132.48 (10)	C9—C10—H10B	109.1
C8—C2—C1	121.26 (10)	H10A—C10—H10B	107.9
C3—C2—C1	105.68 (9)	C12—C11—C10	109.53 (10)
C5—C3—C2	129.11 (10)	C12—C11—H11A	109.8
C5—C3—C4	123.00 (10)	C10—C11—H11A	109.8
C2—C3—C4	105.65 (9)	C12—C11—H11B	109.8
O3—C4—O2	118.88 (10)	C10—C11—H11B	109.8
O3—C4—C3	133.12 (11)	H11A—C11—H11B	108.2
O2—C4—C3	107.95 (9)	C15—C12—C13	106.77 (10)
C3—C5—C6	121.49 (10)	C15—C12—C11	130.04 (10)
C3—C5—C7	124.14 (10)	C13—C12—C11	123.17 (10)
C6—C5—C7	114.32 (10)	C14—C13—C8	131.14 (10)
C5—C6—H6A	109.5	C14—C13—C12	106.24 (10)
C5—C6—H6B	109.5	C8—C13—C12	122.00 (10)
H6A—C6—H6B	109.5	O4—C14—C13	109.47 (9)
C5—C6—H6C	109.5	O4—C14—C16	115.24 (9)
H6A—C6—H6C	109.5	C13—C14—C16	135.09 (10)
H6B—C6—H6C	109.5	C12—C15—O4	109.70 (9)
C5—C7—H7A	109.5	C12—C15—C17	134.46 (10)
C5—C7—H7B	109.5	O4—C15—C17	115.83 (10)
H7A—C7—H7B	109.5	C14—C16—H16A	109.5
C5—C7—H7C	109.5	C14—C16—H16B	109.5
H7A—C7—H7C	109.5	H16A—C16—H16B	109.5
H7B—C7—H7C	109.5	C14—C16—H16C	109.5
C2—C8—C13	126.50 (10)	H16A—C16—H16C	109.5
C2—C8—C9	121.76 (10)	H16B—C16—H16C	109.5
C13—C8—C9	111.74 (10)	C15—C17—H17A	109.5
C8—C9—C10	108.60 (9)	C15—C17—H17B	109.5
C8—C9—H9A	110.0	H17A—C17—H17B	109.5
C10—C9—H9A	110.0	C15—C17—H17C	109.5
C8—C9—H9B	110.0	H17A—C17—H17C	109.5
C10—C9—H9B	110.0	H17B—C17—H17C	109.5
C2—C8—C13—C14	28.51 (18)	C2—C8—C13—C12	−161.82 (10)
C3—C2—C8—C13	16.47 (19)	C1—C2—C3—C5	−147.93 (11)
C8—C2—C3—C5	41.06 (19)

(II-E) 3-[(E)-1,3-dimethyl-5,6,7,8-tetrahydro-4H- cyclohepta[c]furan-4-ylidene]-4-isopropylidenetetrahydrofuran-2,5-dione

Crystal data

C18H20O4	F(000) = 640
Mr = 300.34	Dx = 1.341 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 17726 reflections
a = 9.1881 (2) Å	θ = 2.9–27.5°
b = 12.0022 (3) Å	µ = 0.09 mm^−1
c = 13.7215 (3) Å	T = 100 K
β = 100.4329 (13)°	Fragment, yellow
V = 1488.16 (6) Å^3	0.30 × 0.30 × 0.20 mm
Z = 4

Data collection

KappaCCD diffractometer	3402 independent reflections
Radiation source: fine-focus sealed tube	2822 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.037
CCD scans	θmax = 27.5°, θmin = 2.9°
Absorption correction: multi-scan (DENZO and SCALEPACK; Otwinowski & Minor, 1997)	h = −11→11
Tmin = 0.972, Tmax = 0.982	k = −15→15
28601 measured reflections	l = −17→17

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.035	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.091	H-atom parameters constrained
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0454P)^2 + 0.3366P] where P = (Fo^2 + 2Fc^2)/3
3402 reflections	(Δ/σ)max < 0.001
203 parameters	Δρmax = 0.24 e Å^−3
0 restraints	Δρmin = −0.22 e Å^−3

Special details

Experimental. General preparation of fulgides (I)–(III): a solution of diethyl isopropylidene succinate (15 mmol) in THF [tetrahydrofuran?] (15 ml) was cooled to 195 K and LDA (7.5 ml, 15 mmol; 2 M, THF/n-heptane/ethylbenzene) was added under an argon atmosphere. After stirring for 1 h the appropriate ketone (10 mmol) dissolved in THF (30 ml) was added via a syringe. The reaction mixture was allowed to warm to room temperature overnight and stirred for an additional 24 h. The reaction progress was monitored by TLC [thin layer chromatography?]. Afterwards the reaction mixture was acidified with aqueous HCl (2 M) and the aqueous layer was extracted with ethyl acetate (3 x 50 ml). The combined organic layers were washed with saturated aqueous NaCl solution, dried over MgSO₄ and the solvent was removed in vacuo. The residue was dissolved in cyclohexane/ethyl acetate (7:3), filtered over silica gel and the solvent removed in vacuo again. The residue was dissolved in ethanol (60 ml) and a saturated aqueous solution of KOH (5 ml) was added. After stirring for 20 h at 343 K the reaction mixture was poured onto ice and acidified with aqueous HCl (2 M). The aqueous layer was extracted with ethyl acetate (3 x 50 ml) and the combined organic layers were washed with saturated aqueous NaCl, dried over MgSO₄ and the solvent was removed in vacuo. The dark brown residue was dissolved in dichloromethane (50 ml) and N,N'-dicyclohexylcarbodiimide (4.13 g, 20 mmol) was added. After stirring for 48 h the reaction mixture was filtered over silica gel and the solvent was removed in vacuo. The products were purified by column chromatography and recrystallized from adapted solvents.

(II-E): yield 12% (recrystallized from cyclohexane); R_f=0.75 (cyclohexane/ethyl acetate 7:3); ¹H NMR (500 MHz, CDCl₃, 25 °C, CDCl₃=7.24 p.p.m.) δ=1.33 (s, 3H; CH₃), 1.61–1.65 (m, 2H; CH₂), 1.82 (s, 3H; CH₃), 1.84 (m, 1H; CH₂), 2.11 (m, 2H; CH₂), 2.15 (s, 3H; CH₃), 2.27 (m, 1H; CH₂), 2.32 (s, 3H; CH₃), 2.54–2.59 (m, 1H; CH₂), 4.05–4.09 p.p.m. (m, 1H; CH₂); ¹³C NMR (126 MHz, CDCl₃, 25 °C, CDCl₃=77.0 p.p.m.) δ=11.2, 13.5, 22.6, 24.2, 26.9, 27.8, 29.1, 33.8, 117.5, 118.4, 121.1, 125.2, 145.0, 145.8, 152.7, 153.4, 163.3, 163.6 p.p.m.; MS (70 eV): m/z (%): 301 (20), 300 (100) [M⁺], 285 (14) [M - CH₃⁺], 257 (30), 243 (14), 241 (21), 213 (18), 128 (13), 115 (13), 43 (84); HRMS (m/z) [M⁺] calcd for C₁₈H₂₀O₄: 300.13616; found 300.13550.

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.12492 (9)	−0.08179 (6)	0.59955 (6)	0.02215 (19)
O2	0.16590 (10)	−0.10488 (7)	0.44519 (6)	0.0293 (2)
O3	0.12198 (9)	−0.02503 (7)	0.75441 (6)	0.0262 (2)
O4	0.20776 (8)	0.44140 (6)	0.50505 (5)	0.01798 (18)
C1	0.17786 (12)	−0.04453 (9)	0.51581 (8)	0.0202 (2)
C2	0.23475 (11)	0.07004 (9)	0.53585 (8)	0.0168 (2)
C3	0.25159 (12)	0.08321 (9)	0.64427 (8)	0.0172 (2)
C4	0.16139 (12)	−0.00611 (9)	0.67754 (8)	0.0197 (2)
C5	0.24428 (11)	0.14295 (9)	0.46082 (8)	0.0166 (2)
C6	0.25284 (11)	0.26413 (9)	0.47010 (7)	0.0164 (2)
C7	0.18172 (12)	0.33271 (9)	0.52588 (8)	0.0170 (2)
C8	0.29788 (12)	0.44209 (9)	0.43448 (8)	0.0181 (2)
C9	0.32620 (12)	0.33669 (9)	0.40900 (8)	0.0179 (2)
C10	0.42607 (13)	0.30229 (10)	0.33801 (9)	0.0225 (2)
H10A	0.5001	0.3616	0.3354	0.027*
H10B	0.3662	0.2941	0.2707	0.027*
C11	0.50655 (13)	0.19235 (10)	0.36850 (9)	0.0235 (3)
H11A	0.5938	0.1870	0.3357	0.028*
H11B	0.5429	0.1933	0.4410	0.028*
C12	0.40986 (13)	0.08885 (10)	0.34218 (9)	0.0240 (3)
H12A	0.4550	0.0258	0.3834	0.029*
H12B	0.4095	0.0694	0.2720	0.029*
C13	0.24857 (12)	0.10289 (10)	0.35710 (8)	0.0206 (2)
H13A	0.1972	0.1573	0.3085	0.025*
H13B	0.1961	0.0307	0.3455	0.025*
C14	0.35545 (12)	0.14023 (9)	0.70774 (8)	0.0180 (2)
C15	0.37122 (14)	0.13546 (10)	0.81852 (8)	0.0236 (3)
H15A	0.2898	0.0917	0.8362	0.035*
H15B	0.3683	0.2112	0.8448	0.035*
H15C	0.4658	0.1004	0.8468	0.035*
C16	0.47023 (13)	0.20922 (9)	0.67179 (8)	0.0213 (2)
H16A	0.4769	0.1872	0.6040	0.032*
H16B	0.5662	0.1976	0.7151	0.032*
H16C	0.4429	0.2881	0.6728	0.032*
C17	0.07966 (13)	0.31605 (9)	0.59678 (9)	0.0219 (2)
H17A	0.1363	0.3157	0.6646	0.033*
H17B	0.0281	0.2447	0.5831	0.033*
H17C	0.0071	0.3767	0.5896	0.033*
C18	0.34789 (13)	0.55382 (9)	0.40774 (9)	0.0226 (2)
H18A	0.4120	0.5458	0.3583	0.034*
H18B	0.4031	0.5901	0.4671	0.034*
H18C	0.2616	0.5993	0.3802	0.034*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0211 (4)	0.0166 (4)	0.0287 (4)	−0.0034 (3)	0.0043 (3)	0.0011 (3)
O2	0.0379 (5)	0.0200 (4)	0.0285 (5)	−0.0045 (4)	0.0020 (4)	−0.0060 (4)
O3	0.0266 (4)	0.0250 (4)	0.0290 (5)	−0.0021 (3)	0.0104 (4)	0.0055 (4)
O4	0.0203 (4)	0.0150 (4)	0.0191 (4)	−0.0011 (3)	0.0048 (3)	0.0011 (3)
C1	0.0171 (5)	0.0175 (5)	0.0250 (6)	0.0002 (4)	0.0010 (4)	0.0006 (4)
C2	0.0138 (5)	0.0160 (5)	0.0201 (5)	0.0000 (4)	0.0017 (4)	−0.0022 (4)
C3	0.0167 (5)	0.0153 (5)	0.0200 (5)	0.0021 (4)	0.0049 (4)	0.0022 (4)
C4	0.0165 (5)	0.0177 (5)	0.0248 (6)	0.0019 (4)	0.0030 (4)	0.0026 (4)
C5	0.0125 (5)	0.0179 (5)	0.0192 (5)	0.0010 (4)	0.0019 (4)	−0.0013 (4)
C6	0.0159 (5)	0.0179 (5)	0.0149 (5)	−0.0001 (4)	0.0019 (4)	0.0009 (4)
C7	0.0176 (5)	0.0152 (5)	0.0176 (5)	−0.0018 (4)	0.0015 (4)	0.0011 (4)
C8	0.0165 (5)	0.0208 (5)	0.0167 (5)	−0.0009 (4)	0.0020 (4)	0.0029 (4)
C9	0.0166 (5)	0.0204 (5)	0.0164 (5)	−0.0010 (4)	0.0018 (4)	0.0020 (4)
C10	0.0222 (6)	0.0260 (6)	0.0207 (6)	0.0013 (5)	0.0077 (4)	0.0029 (5)
C11	0.0200 (6)	0.0308 (6)	0.0209 (6)	0.0049 (5)	0.0066 (4)	0.0009 (5)
C12	0.0264 (6)	0.0268 (6)	0.0194 (5)	0.0072 (5)	0.0057 (4)	−0.0011 (5)
C13	0.0227 (6)	0.0204 (5)	0.0179 (5)	0.0019 (4)	0.0016 (4)	−0.0014 (4)
C14	0.0197 (5)	0.0142 (5)	0.0202 (5)	0.0028 (4)	0.0039 (4)	0.0007 (4)
C15	0.0297 (6)	0.0211 (6)	0.0191 (5)	−0.0007 (5)	0.0021 (5)	0.0007 (4)
C16	0.0217 (6)	0.0192 (6)	0.0223 (6)	−0.0036 (4)	0.0023 (4)	−0.0006 (4)
C17	0.0237 (6)	0.0183 (5)	0.0257 (6)	0.0001 (4)	0.0098 (5)	0.0002 (4)
C18	0.0237 (6)	0.0204 (6)	0.0231 (6)	−0.0025 (5)	0.0026 (5)	0.0047 (5)

Geometric parameters (Å, º)

O1—C4	1.3975 (14)	C11—C12	1.5319 (17)
O1—C1	1.3997 (14)	C11—H11A	0.9900
O2—C1	1.1988 (14)	C11—H11B	0.9900
O3—C4	1.1973 (14)	C12—C13	1.5416 (16)
O4—C7	1.3658 (13)	C12—H12A	0.9900
O4—C8	1.3834 (13)	C12—H12B	0.9900
C1—C2	1.4790 (15)	C13—H13A	0.9900
C2—C5	1.3661 (15)	C13—H13B	0.9900
C2—C3	1.4761 (15)	C14—C16	1.4931 (15)
C3—C14	1.3552 (16)	C14—C15	1.5017 (15)
C3—C4	1.4770 (15)	C15—H15A	0.9800
C5—C6	1.4609 (15)	C15—H15B	0.9800
C5—C13	1.5094 (15)	C15—H15C	0.9800
C6—C7	1.3679 (15)	C16—H16A	0.9800
C6—C9	1.4562 (15)	C16—H16B	0.9800
C7—C17	1.4820 (15)	C16—H16C	0.9800
C7—C14	3.5594 (15)	C17—H17A	0.9800
C8—C9	1.3503 (16)	C17—H17B	0.9800
C8—C18	1.4849 (15)	C17—H17C	0.9800
C9—C10	1.5117 (15)	C18—H18A	0.9800
C10—C11	1.5332 (16)	C18—H18B	0.9800
C10—H10A	0.9900	C18—H18C	0.9800
C10—H10B	0.9900
C4—O1—C1	110.50 (8)	H11A—C11—H11B	107.7
C7—O4—C8	107.57 (8)	C11—C12—C13	114.23 (9)
O2—C1—O1	118.41 (10)	C11—C12—H12A	108.7
O2—C1—C2	133.60 (11)	C13—C12—H12A	108.7
O1—C1—C2	107.94 (9)	C11—C12—H12B	108.7
C5—C2—C3	132.98 (10)	C13—C12—H12B	108.7
C5—C2—C1	121.61 (10)	H12A—C12—H12B	107.6
C3—C2—C1	104.83 (9)	C5—C13—C12	110.48 (9)
C14—C3—C2	129.41 (10)	C5—C13—H13A	109.6
C14—C3—C4	122.49 (10)	C12—C13—H13A	109.6
C2—C3—C4	105.75 (9)	C5—C13—H13B	109.6
O3—C4—O1	118.85 (10)	C12—C13—H13B	109.6
O3—C4—C3	133.32 (11)	H13A—C13—H13B	108.1
O1—C4—C3	107.77 (9)	C3—C14—C16	121.68 (10)
C2—C5—C6	125.58 (10)	C3—C14—C15	123.98 (10)
C2—C5—C13	121.52 (10)	C16—C14—C15	114.27 (10)
C6—C5—C13	112.90 (9)	C14—C15—H15A	109.5
C7—C6—C9	106.26 (10)	C14—C15—H15B	109.5
C7—C6—C5	128.62 (10)	H15A—C15—H15B	109.5
C9—C6—C5	124.64 (9)	C14—C15—H15C	109.5
O4—C7—C6	109.76 (9)	H15A—C15—H15C	109.5
O4—C7—C17	114.95 (9)	H15B—C15—H15C	109.5
C6—C7—C17	135.17 (10)	C14—C16—H16A	109.5
C9—C8—O4	110.08 (9)	C14—C16—H16B	109.5
C9—C8—C18	134.37 (10)	H16A—C16—H16B	109.5
O4—C8—C18	115.44 (9)	C14—C16—H16C	109.5
C8—C9—C6	106.28 (9)	H16A—C16—H16C	109.5
C8—C9—C10	126.21 (10)	H16B—C16—H16C	109.5
C6—C9—C10	127.30 (10)	C7—C17—H17A	109.5
C9—C10—C11	112.23 (9)	C7—C17—H17B	109.5
C9—C10—H10A	109.2	H17A—C17—H17B	109.5
C11—C10—H10A	109.2	C7—C17—H17C	109.5
C9—C10—H10B	109.2	H17A—C17—H17C	109.5
C11—C10—H10B	109.2	H17B—C17—H17C	109.5
H10A—C10—H10B	107.9	C8—C18—H18A	109.5
C12—C11—C10	113.78 (10)	C8—C18—H18B	109.5
C12—C11—H11A	108.8	H18A—C18—H18B	109.5
C10—C11—H11A	108.8	C8—C18—H18C	109.5
C12—C11—H11B	108.8	H18A—C18—H18C	109.5
C10—C11—H11B	108.8	H18B—C18—H18C	109.5
C2—C5—C6—C7	−37.86 (17)	C2—C5—C6—C9	151.11 (11)
C3—C2—C5—C6	−10.38 (19)	C1—C2—C3—C14	144.83 (11)
C5—C2—C3—C14	−44.14 (19)

(II-Z) 3-[(Z)-1,3-dimethyl-5,6,7,8-tetrahydro-4H-cyclohepta[c]furan-4-ylidene]-4-isopropylidenetetrahydrofuran-2,5-dione

Crystal data

C18H20O4	F(000) = 1280
Mr = 300.34	Dx = 1.319 Mg m^−3
Orthorhombic, Pbca	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2ab	Cell parameters from 45246 reflections
a = 8.7024 (2) Å	θ = 2.9–27.5°
b = 12.8964 (4) Å	µ = 0.09 mm^−1
c = 26.9492 (7) Å	T = 100 K
V = 3024.50 (14) Å^3	Fragment, yellow
Z = 8	0.30 × 0.30 × 0.26 mm

Data collection

KappaCCD diffractometer	3444 independent reflections
Radiation source: fine-focus sealed tube	2657 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.063
CCD scans	θmax = 27.4°, θmin = 2.9°
Absorption correction: multi-scan (DENZO and SCALEPACK; Otwinowski & Minor, 1997)	h = −11→11
Tmin = 0.973, Tmax = 0.976	k = −16→16
29108 measured reflections	l = −34→34

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.097	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0423P)^2 + 0.8467P] where P = (Fo^2 + 2Fc^2)/3
3444 reflections	(Δ/σ)max < 0.001
203 parameters	Δρmax = 0.21 e Å^−3
0 restraints	Δρmin = −0.19 e Å^−3

Special details

Experimental. General preparation of fulgides (I)–(III): a solution of diethyl isopropylidene succinate (15 mmol) in THF [tetrahydrofuran?] (15 ml) was cooled to 195 K and LDA (7.5 ml, 15 mmol; 2 M, THF/n-heptane/ethylbenzene) was added under an argon atmosphere. After stirring for 1 h the appropriate ketone (10 mmol) dissolved in THF (30 ml) was added via a syringe. The reaction mixture was allowed to warm to room temperature overnight and stirred for an additional 24 h. The reaction progress was monitored by TLC [thin layer chromatography?]. Afterwards the reaction mixture was acidified with aqueous HCl (2 M) and the aqueous layer was extracted with ethyl acetate (3 x 50 ml). The combined organic layers were washed with saturated aqueous NaCl solution, dried over MgSO₄ and the solvent was removed in vacuo. The residue was dissolved in cyclohexane/ethyl acetate (7:3), filtered over silica gel and the solvent removed in vacuo again. The residue was dissolved in ethanol (60 ml) and a saturated aqueous solution of KOH (5 ml) was added. After stirring for 20 h at 343 K the reaction mixture was poured onto ice and acidified with aqueous HCl (2 M). The aqueous layer was extracted with ethyl acetate (3 x 50 ml) and the combined organic layers were washed with saturated aqueous NaCl, dried over MgSO₄ and the solvent was removed in vacuo. The dark brown residue was dissolved in dichloromethane (50 ml) and N,N'-dicyclohexylcarbodiimide (4.13 g, 20 mmol) was added. After stirring for 48 h the reaction mixture was filtered over silica gel and the solvent was removed in vacuo. The products were purified by column chromatography and recrystallized from adapted solvents.

(II-Z): yield 9% (recrystallized from cyclohexane); R_f=0.65 (cyclohexane/ethyl acetate 7:3); ¹H NMR (500 MHz, CDCl₃, 25 °C, CDCl₃=7.24 p.p.m.) δ=1.41–1.55 (m, 2H; CH₂), 1.90 (m, 1H; CH₂), 1.94 (s, 3H; CH₃), 2.04 (m, 1H; CH₂), 2.13 (s, 3H; CH₃), 2.16 (s, 3H; CH₃), 2.18 (m, 1H; CH₂), 2.24 (m, 1H; CH₂), 2.38 (s, 3H; CH₃), 2.55–2.62 p.p.m. (m, 2H; CH₂); ¹³C NMR (126 MHz, CDCl₃, 25 °C, CDCl₃=77.0 p.p.m.) δ=11.2, 13.3, 22.1, 25.2, 26.5, 28.4, 29.8, 37.6, 117.8, 118.2, 121.3, 121.8, 145.0, 151.2, 152.2, 153.4, 161.1, 163.8 p.p.m.; MS (70 eV): m/z (%): 301 (21), 300 (100) [M⁺], 285 (17) [M - CH₃⁺], 257 (35), 255 (16), 243 (16), 241 (23), 239 (18), 229 (15), 213 (25), 211 (18), 185 (16), 128 (16), 115 (16), 43 (92); HRMS (m/z) [M⁺] calcd for C₁₈H₂₀O₄: 300.13616; found 300.13330.

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.53129 (11)	0.43365 (7)	0.11324 (3)	0.0273 (2)
O2	0.53720 (11)	0.56871 (8)	0.16557 (3)	0.0314 (2)
O3	0.48045 (12)	0.32049 (7)	0.05236 (4)	0.0329 (2)
O4	0.35706 (10)	0.85114 (7)	0.17899 (3)	0.0254 (2)
C1	0.47246 (14)	0.52835 (11)	0.13159 (5)	0.0243 (3)
C2	0.32999 (14)	0.55136 (10)	0.10408 (5)	0.0220 (3)
C3	0.32620 (14)	0.47785 (10)	0.06239 (5)	0.0227 (3)
C4	0.44516 (15)	0.39940 (10)	0.07322 (5)	0.0255 (3)
C5	0.21609 (14)	0.61393 (10)	0.12253 (4)	0.0212 (3)
C6	0.25087 (15)	0.70148 (10)	0.15504 (4)	0.0216 (3)
C7	0.36679 (15)	0.77046 (10)	0.14635 (5)	0.0236 (3)
C8	0.23199 (15)	0.83183 (10)	0.20975 (5)	0.0244 (3)
C9	0.16277 (14)	0.74260 (10)	0.19642 (4)	0.0226 (3)
C10	0.02622 (15)	0.69378 (11)	0.22104 (5)	0.0258 (3)
H10A	−0.0157	0.7429	0.2458	0.031*
H10B	0.0604	0.6310	0.2391	0.031*
C11	−0.10143 (15)	0.66369 (11)	0.18522 (5)	0.0254 (3)
H11A	−0.1271	0.7244	0.1643	0.030*
H11B	−0.1943	0.6453	0.2045	0.030*
C12	−0.05940 (14)	0.57284 (10)	0.15162 (5)	0.0241 (3)
H12A	−0.1556	0.5438	0.1378	0.029*
H12B	−0.0117	0.5183	0.1723	0.029*
C13	0.05009 (14)	0.59670 (10)	0.10810 (5)	0.0228 (3)
H13A	0.0455	0.5384	0.0842	0.027*
H13B	0.0124	0.6594	0.0908	0.027*
C14	0.26593 (15)	0.48959 (10)	0.01639 (4)	0.0244 (3)
C15	0.18760 (15)	0.58745 (11)	0.00039 (5)	0.0281 (3)
H15A	0.0770	0.5748	−0.0030	0.042*
H15B	0.2295	0.6099	−0.0316	0.042*
H15C	0.2050	0.6416	0.0253	0.042*
C16	0.28152 (16)	0.40756 (11)	−0.02309 (5)	0.0316 (3)
H16A	0.3879	0.3827	−0.0240	0.047*
H16B	0.2542	0.4371	−0.0554	0.047*
H16C	0.2126	0.3496	−0.0155	0.047*
C17	0.49192 (16)	0.77903 (11)	0.10941 (5)	0.0308 (3)
H17A	0.5062	0.8520	0.1003	0.046*
H17B	0.4651	0.7389	0.0798	0.046*
H17C	0.5874	0.7519	0.1237	0.046*
C18	0.20589 (16)	0.91077 (11)	0.24902 (5)	0.0319 (3)
H18A	0.1167	0.8908	0.2691	0.048*
H18B	0.1868	0.9784	0.2336	0.048*
H18C	0.2970	0.9152	0.2703	0.048*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0255 (5)	0.0281 (5)	0.0283 (5)	0.0044 (4)	0.0000 (4)	0.0009 (4)
O2	0.0249 (5)	0.0407 (6)	0.0287 (5)	0.0018 (4)	−0.0044 (4)	−0.0051 (4)
O3	0.0373 (6)	0.0240 (5)	0.0376 (5)	0.0030 (4)	0.0068 (4)	−0.0011 (4)
O4	0.0247 (5)	0.0246 (5)	0.0269 (5)	−0.0023 (4)	0.0013 (4)	−0.0036 (4)
C1	0.0224 (6)	0.0275 (7)	0.0231 (6)	0.0008 (6)	0.0041 (5)	0.0012 (5)
C2	0.0206 (6)	0.0235 (7)	0.0220 (6)	−0.0020 (5)	0.0007 (5)	0.0006 (5)
C3	0.0213 (6)	0.0212 (6)	0.0256 (6)	−0.0013 (5)	0.0030 (5)	0.0005 (5)
C4	0.0261 (7)	0.0246 (7)	0.0258 (6)	−0.0018 (6)	0.0050 (5)	0.0020 (5)
C5	0.0225 (6)	0.0225 (6)	0.0188 (6)	−0.0017 (5)	0.0010 (5)	0.0030 (5)
C6	0.0202 (6)	0.0233 (6)	0.0214 (6)	0.0015 (5)	−0.0002 (5)	0.0013 (5)
C7	0.0234 (6)	0.0244 (7)	0.0228 (6)	0.0001 (5)	0.0003 (5)	−0.0023 (5)
C8	0.0215 (6)	0.0283 (7)	0.0232 (6)	0.0022 (6)	0.0012 (5)	−0.0012 (5)
C9	0.0211 (6)	0.0260 (7)	0.0208 (6)	0.0019 (5)	−0.0005 (5)	−0.0010 (5)
C10	0.0241 (7)	0.0304 (7)	0.0229 (6)	0.0005 (6)	0.0027 (5)	−0.0017 (5)
C11	0.0206 (6)	0.0277 (7)	0.0278 (7)	0.0004 (5)	0.0031 (5)	0.0000 (5)
C12	0.0201 (6)	0.0258 (7)	0.0264 (6)	−0.0023 (5)	0.0012 (5)	0.0004 (5)
C13	0.0217 (6)	0.0236 (7)	0.0231 (6)	−0.0005 (5)	0.0004 (5)	−0.0009 (5)
C14	0.0209 (6)	0.0272 (7)	0.0251 (6)	−0.0041 (5)	0.0036 (5)	−0.0010 (5)
C15	0.0263 (7)	0.0347 (8)	0.0233 (6)	−0.0018 (6)	0.0001 (5)	0.0019 (6)
C16	0.0299 (7)	0.0363 (8)	0.0285 (7)	−0.0001 (6)	0.0015 (6)	−0.0073 (6)
C17	0.0305 (7)	0.0293 (8)	0.0327 (7)	−0.0069 (6)	0.0078 (6)	−0.0033 (6)
C18	0.0313 (7)	0.0328 (8)	0.0315 (7)	−0.0004 (6)	0.0007 (6)	−0.0099 (6)

Geometric parameters (Å, º)

O1—C4	1.3856 (16)	C11—C12	1.5253 (18)
O1—C1	1.4136 (16)	C11—H11A	0.9900
O2—C1	1.1945 (15)	C11—H11B	0.9900
O3—C4	1.2026 (16)	C12—C13	1.5421 (17)
O4—C7	1.3652 (15)	C12—H12A	0.9900
O4—C8	1.3905 (15)	C12—H12B	0.9900
C1—C2	1.4748 (17)	C13—H13A	0.9900
C2—C5	1.3715 (18)	C13—H13B	0.9900
C2—C3	1.4704 (17)	C14—C15	1.4979 (19)
C3—C14	1.3544 (17)	C14—C16	1.5064 (18)
C3—C4	1.4766 (18)	C15—H15A	0.9800
C5—C6	1.4608 (17)	C15—H15B	0.9800
C5—C13	1.5124 (17)	C15—H15C	0.9800
C6—C7	1.3653 (18)	C16—H16A	0.9800
C6—C9	1.4534 (17)	C16—H16B	0.9800
C7—C14	5.1143 (18)	C16—H16C	0.9800
C7—C17	1.4795 (18)	C17—H17A	0.9800
C8—C9	1.3477 (18)	C17—H17B	0.9800
C8—C18	1.4859 (18)	C17—H17C	0.9800
C9—C10	1.4996 (18)	C18—H18A	0.9800
C10—C11	1.5220 (18)	C18—H18B	0.9800
C10—H10A	0.9900	C18—H18C	0.9800
C10—H10B	0.9900
C4—O1—C1	110.60 (10)	H11A—C11—H11B	107.7
C7—O4—C8	107.23 (10)	C11—C12—C13	116.52 (11)
O2—C1—O1	118.29 (12)	C11—C12—H12A	108.2
O2—C1—C2	133.96 (13)	C13—C12—H12A	108.2
O1—C1—C2	107.60 (11)	C11—C12—H12B	108.2
C5—C2—C3	129.80 (12)	C13—C12—H12B	108.2
C5—C2—C1	122.94 (11)	H12A—C12—H12B	107.3
C3—C2—C1	105.86 (11)	C5—C13—C12	115.08 (10)
C14—C3—C2	129.49 (12)	C5—C13—H13A	108.5
C14—C3—C4	121.94 (12)	C12—C13—H13A	108.5
C2—C3—C4	105.96 (11)	C5—C13—H13B	108.5
O3—C4—O1	119.70 (12)	C12—C13—H13B	108.5
O3—C4—C3	131.79 (13)	H13A—C13—H13B	107.5
O1—C4—C3	108.35 (11)	C3—C14—C15	122.27 (12)
C2—C5—C6	121.49 (11)	C3—C14—C16	122.21 (12)
C2—C5—C13	120.71 (12)	C15—C14—C16	115.42 (11)
C6—C5—C13	117.76 (11)	C14—C15—H15A	109.5
C7—C6—C9	106.48 (11)	C14—C15—H15B	109.5
C7—C6—C5	123.63 (11)	H15A—C15—H15B	109.5
C9—C6—C5	129.26 (11)	C14—C15—H15C	109.5
O4—C7—C6	109.89 (11)	H15A—C15—H15C	109.5
O4—C7—C17	114.98 (11)	H15B—C15—H15C	109.5
C6—C7—C17	135.07 (12)	C14—C16—H16A	109.5
C9—C8—O4	110.12 (11)	C14—C16—H16B	109.5
C9—C8—C18	134.95 (12)	H16A—C16—H16B	109.5
O4—C8—C18	114.93 (11)	C14—C16—H16C	109.5
C8—C9—C6	106.28 (11)	H16A—C16—H16C	109.5
C8—C9—C10	126.49 (12)	H16B—C16—H16C	109.5
C6—C9—C10	127.18 (12)	C7—C17—H17A	109.5
C9—C10—C11	113.87 (10)	C7—C17—H17B	109.5
C9—C10—H10A	108.8	H17A—C17—H17B	109.5
C11—C10—H10A	108.8	C7—C17—H17C	109.5
C9—C10—H10B	108.8	H17A—C17—H17C	109.5
C11—C10—H10B	108.8	H17B—C17—H17C	109.5
H10A—C10—H10B	107.7	C8—C18—H18A	109.5
C10—C11—C12	113.42 (11)	C8—C18—H18B	109.5
C10—C11—H11A	108.9	H18A—C18—H18B	109.5
C12—C11—H11A	108.9	C8—C18—H18C	109.5
C10—C11—H11B	108.9	H18A—C18—H18C	109.5
C12—C11—H11B	108.9	H18B—C18—H18C	109.5
C2—C5—C6—C7	44.98 (18)	C2—C5—C6—C9	−145.41 (13)
C3—C2—C5—C6	−163.10 (12)	C1—C2—C3—C14	−148.71 (13)
C5—C2—C3—C14	44.8 (2)

(III-E) 3-isopropylidene-4-[(E)-1-(5-methoxy-2-methyl-1-benzofuran-3- yl)ethylidene]tetrahydrofuran-2,5-dione

Crystal data

C19H18O5	Z = 4
Mr = 326.33	F(000) = 688
Triclinic, P1	Dx = 1.355 Mg m^−3
a = 7.1750 (2) Å	Mo Kα radiation, λ = 0.71073 Å
b = 12.0569 (2) Å	Cell parameters from 28103 reflections
c = 19.9592 (4) Å	θ = 2.9–27.5°
α = 103.8136 (12)°	µ = 0.10 mm^−1
β = 91.1022 (13)°	T = 100 K
γ = 106.5927 (12)°	Fragment, colourless
V = 1599.77 (6) Å^3	0.30 × 0.25 × 0.09 mm

Data collection

KappaCCD diffractometer	7318 independent reflections
Radiation source: fine-focus sealed tube	5802 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.040
CCD scans	θmax = 27.5°, θmin = 3.0°
Absorption correction: multi-scan (DENZO and SCALEPACK; Otwinowski & Minor, 1997)	h = −9→9
Tmin = 0.971, Tmax = 0.991	k = −15→14
38746 measured reflections	l = −25→25

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.040	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.107	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0575P)^2 + 0.2713P] where P = (Fo^2 + 2Fc^2)/3
7318 reflections	(Δ/σ)max = 0.001
443 parameters	Δρmax = 0.22 e Å^−3
0 restraints	Δρmin = −0.28 e Å^−3

Special details

Experimental. General preparation of fulgides (I)–(III): a solution of diethyl isopropylidene succinate (15 mmol) in THF [tetrahydrofuran?] (15 ml) was cooled to 195 K and LDA (7.5 ml, 15 mmol; 2 M, THF/n-heptane/ethylbenzene) was added under an argon atmosphere. After stirring for 1 h the appropriate ketone (10 mmol) dissolved in THF (30 ml) was added via a syringe. The reaction mixture was allowed to warm to room temperature overnight and stirred for an additional 24 h. The reaction progress was monitored by TLC [thin layer chromatography?]. Afterwards the reaction mixture was acidified with aqueous HCl (2 M) and the aqueous layer was extracted with ethyl acetate (3 x 50 ml). The combined organic layers were washed with saturated aqueous NaCl solution, dried over MgSO₄ and the solvent was removed in vacuo. The residue was dissolved in cyclohexane/ethyl acetate (7:3), filtered over silica gel and the solvent removed in vacuo again. The residue was dissolved in ethanol (60 ml) and a saturated aqueous solution of KOH (5 ml) was added. After stirring for 20 h at 343 K the reaction mixture was poured onto ice and acidified with aqueous HCl (2 M). The aqueous layer was extracted with ethyl acetate (3 x 50 ml) and the combined organic layers were washed with saturated aqueous NaCl, dried over MgSO₄ and the solvent was removed in vacuo. The dark brown residue was dissolved in dichloromethane (50 ml) and N,N'-dicyclohexylcarbodiimide (4.13 g, 20 mmol) was added. After stirring for 48 h the reaction mixture was filtered over silica gel and the solvent was removed in vacuo. The products were purified by column chromatography and recrystallized from adapted solvents.

(III-E): yield 13% (recrystallized from diethyl ether); R_f=0.26 (cyclohexane/ethyl acetate 9:1); ¹H NMR (500 MHz, CDCl₃, 25 °C, CDCl₃=7.24 p.p.m.) δ=1.12 (s, 3H; CH₃), 2.23 (s, 6H; CH₃), 2.72 (s, 3H; CH₃), 3.79 (s, 3H; CH₃), 6.70 (d, ⁴J(H,H)=2.5 Hz, 1H; Ar—H), 6.85 (dd, ³J(H,H)=9.4 Hz, ⁴J(H,H)=2.5 Hz, 1H; Ar—H), 7.29 p.p.m. (d, ³J(H,H)=9.4 Hz, 1H; Ar—H); ¹³C NMR (126 MHz, CDCl₃, 25 °C, CDCl₃=77.0 p.p.m.) δ=14.0, 22.0, 22.7, 26.7, 55.9, 102.8, 111.6, 112.9, 119.6, 120.8, 121.5, 126.5, 145.0, 148.9, 153.5, 155.5, 156.2, 163.0, 163.6 p.p.m.; MS (70 eV): m/z (%): 327 (22), 326 (100) [M+], 311 (43), 309 (12), 283 (20), 281 (12), 267 (41), 265 (15), 253 (13), 239 (17), 223 (11), 204 (11), 165 (11), 162 (21), 152 (12), 115 (13), 106 (12), 91 (12), 77 (10), 44 (12), 43 (16); HRMS (m/z) [M⁺] calcd for C₁₉H₁₈O₅ + Na⁺: 349.10464; found 349.10480; calcd for (C₁₉H₁₈O₅)₂ + Na⁺: 675.22026; found 675.22007.

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
O1	0.83247 (13)	0.42934 (8)	−0.10941 (5)	0.0278 (2)
O2	0.84769 (13)	0.57350 (8)	−0.01315 (5)	0.0276 (2)
O3	0.78118 (16)	0.25524 (10)	−0.18915 (5)	0.0395 (3)
O4	0.54766 (12)	0.08759 (7)	0.09187 (4)	0.02121 (19)
O5	−0.03222 (13)	0.25903 (8)	0.20856 (5)	0.0249 (2)
O6	0.19367 (13)	1.06123 (8)	0.57325 (5)	0.0270 (2)
O7	0.24410 (13)	1.08504 (8)	0.46656 (5)	0.0286 (2)
O8	0.12701 (16)	0.98909 (10)	0.66622 (5)	0.0371 (3)
O9	0.01193 (12)	0.50256 (7)	0.40880 (4)	0.02073 (19)
O10	0.68627 (13)	0.55086 (8)	0.27943 (5)	0.0271 (2)
C1	0.77789 (18)	0.47028 (11)	−0.04341 (7)	0.0229 (3)
C2	0.64341 (17)	0.36724 (10)	−0.02416 (6)	0.0194 (2)
C3	0.58961 (18)	0.26948 (11)	−0.08837 (6)	0.0212 (3)
C4	0.73649 (19)	0.30723 (12)	−0.13588 (7)	0.0261 (3)
C5	0.41913 (18)	0.18098 (11)	−0.11029 (6)	0.0211 (3)
C6	0.3731 (2)	0.09948 (12)	−0.18220 (6)	0.0264 (3)
H6A	0.4871	0.1173	−0.2085	0.040*
H6B	0.2621	0.1119	−0.2055	0.040*
H6C	0.3400	0.0161	−0.1795	0.040*
C7	0.25495 (18)	0.16127 (11)	−0.06501 (7)	0.0245 (3)
H7A	0.2666	0.1032	−0.0394	0.037*
H7B	0.1300	0.1305	−0.0938	0.037*
H7C	0.2609	0.2372	−0.0322	0.037*
C8	0.60882 (17)	0.37010 (10)	0.04286 (6)	0.0191 (2)
C9	0.65576 (18)	0.48588 (11)	0.09897 (6)	0.0217 (3)
H9A	0.7960	0.5138	0.1138	0.033*
H9B	0.5820	0.4724	0.1386	0.033*
H9C	0.6197	0.5464	0.0809	0.033*
C10	0.54151 (17)	0.26032 (10)	0.06656 (6)	0.0188 (2)
C11	0.39070 (17)	0.23068 (10)	0.11249 (6)	0.0187 (2)
C12	0.24555 (17)	0.28075 (11)	0.13935 (6)	0.0200 (2)
H12	0.2343	0.3524	0.1301	0.024*
C13	0.11888 (17)	0.22168 (11)	0.17993 (6)	0.0209 (3)
C14	0.13627 (18)	0.11643 (11)	0.19469 (6)	0.0224 (3)
H14	0.0499	0.0798	0.2240	0.027*
C15	0.27723 (18)	0.06540 (11)	0.16719 (6)	0.0226 (3)
H15	0.2886	−0.0064	0.1762	0.027*
C16	0.40091 (18)	0.12450 (10)	0.12591 (6)	0.0203 (2)
C17	0.62971 (17)	0.17192 (10)	0.05623 (6)	0.0193 (2)
C18	0.79861 (18)	0.15372 (11)	0.01844 (6)	0.0222 (3)
H18A	0.7516	0.0930	−0.0255	0.033*
H18B	0.8816	0.1269	0.0467	0.033*
H18C	0.8743	0.2292	0.0092	0.033*
C19	−0.0470 (2)	0.37033 (12)	0.19978 (7)	0.0266 (3)
H19A	0.0734	0.4341	0.2202	0.040*
H19B	−0.1581	0.3883	0.2229	0.040*
H19C	−0.0664	0.3651	0.1503	0.040*
C20	0.23237 (17)	1.02088 (11)	0.50498 (7)	0.0225 (3)
C21	0.23856 (17)	0.89626 (10)	0.49370 (6)	0.0199 (2)
C22	0.23080 (17)	0.87166 (11)	0.56294 (6)	0.0212 (3)
C23	0.17559 (19)	0.97184 (12)	0.60832 (7)	0.0257 (3)
C24	0.30070 (17)	0.79572 (11)	0.58899 (6)	0.0217 (3)
C25	0.2977 (2)	0.79252 (13)	0.66383 (7)	0.0291 (3)
H25A	0.4298	0.8305	0.6874	0.044*
H25B	0.2520	0.7092	0.6668	0.044*
H25C	0.2095	0.8358	0.6861	0.044*
C26	0.39663 (18)	0.71076 (11)	0.54697 (7)	0.0228 (3)
H26A	0.3006	0.6316	0.5304	0.034*
H26B	0.5040	0.7050	0.5758	0.034*
H26C	0.4481	0.7401	0.5072	0.034*
C27	0.22750 (17)	0.82663 (10)	0.42822 (6)	0.0195 (2)
C28	0.25997 (19)	0.87850 (11)	0.36601 (7)	0.0238 (3)
H28A	0.1476	0.9045	0.3556	0.036*
H28B	0.2750	0.8174	0.3260	0.036*
H28C	0.3784	0.9472	0.3761	0.036*
C29	0.17468 (17)	0.69556 (10)	0.41283 (6)	0.0188 (2)
C30	0.27989 (18)	0.61997 (10)	0.37302 (6)	0.0193 (2)
C31	0.45498 (18)	0.64168 (11)	0.34141 (6)	0.0211 (2)
H31	0.5284	0.7204	0.3405	0.025*
C32	0.51657 (18)	0.54338 (11)	0.31157 (6)	0.0214 (3)
C33	0.40928 (19)	0.42672 (11)	0.31314 (6)	0.0228 (3)
H33	0.4557	0.3616	0.2920	0.027*
C34	0.23757 (18)	0.40485 (11)	0.34486 (6)	0.0216 (3)
H34	0.1652	0.3264	0.3467	0.026*
C35	0.17672 (18)	0.50393 (11)	0.37380 (6)	0.0199 (2)
C36	0.01579 (18)	0.62109 (10)	0.43240 (6)	0.0198 (2)
C37	−0.15005 (18)	0.64132 (11)	0.47109 (7)	0.0225 (3)
H37A	−0.1381	0.6253	0.5166	0.034*
H37B	−0.2728	0.5876	0.4452	0.034*
H37C	−0.1492	0.7246	0.4772	0.034*
C38	0.7970 (2)	0.66647 (12)	0.27383 (7)	0.0302 (3)
H38A	0.7176	0.6974	0.2468	0.045*
H38B	0.9143	0.6607	0.2506	0.045*
H38C	0.8353	0.7208	0.3202	0.045*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0245 (5)	0.0323 (5)	0.0258 (5)	0.0029 (4)	0.0064 (4)	0.0125 (4)
O2	0.0243 (5)	0.0209 (5)	0.0378 (5)	0.0035 (4)	0.0022 (4)	0.0118 (4)
O3	0.0361 (6)	0.0494 (6)	0.0261 (5)	0.0055 (5)	0.0130 (4)	0.0046 (5)
O4	0.0223 (4)	0.0198 (4)	0.0238 (4)	0.0076 (3)	0.0067 (3)	0.0077 (3)
O5	0.0221 (5)	0.0290 (5)	0.0273 (5)	0.0108 (4)	0.0094 (4)	0.0099 (4)
O6	0.0269 (5)	0.0211 (4)	0.0300 (5)	0.0094 (4)	0.0001 (4)	−0.0018 (4)
O7	0.0264 (5)	0.0194 (4)	0.0405 (6)	0.0065 (4)	0.0037 (4)	0.0086 (4)
O8	0.0450 (6)	0.0459 (6)	0.0229 (5)	0.0259 (5)	0.0019 (4)	−0.0014 (4)
O9	0.0220 (4)	0.0174 (4)	0.0229 (4)	0.0061 (3)	0.0049 (3)	0.0048 (3)
O10	0.0239 (5)	0.0281 (5)	0.0299 (5)	0.0101 (4)	0.0091 (4)	0.0052 (4)
C1	0.0179 (6)	0.0273 (7)	0.0271 (6)	0.0074 (5)	0.0025 (5)	0.0132 (5)
C2	0.0166 (6)	0.0194 (6)	0.0230 (6)	0.0051 (5)	0.0022 (5)	0.0071 (5)
C3	0.0220 (6)	0.0250 (6)	0.0193 (6)	0.0090 (5)	0.0049 (5)	0.0082 (5)
C4	0.0229 (6)	0.0319 (7)	0.0226 (6)	0.0055 (5)	0.0044 (5)	0.0084 (5)
C5	0.0226 (6)	0.0221 (6)	0.0210 (6)	0.0088 (5)	0.0017 (5)	0.0075 (5)
C6	0.0281 (7)	0.0277 (7)	0.0216 (6)	0.0074 (5)	0.0004 (5)	0.0042 (5)
C7	0.0203 (6)	0.0242 (6)	0.0251 (6)	0.0022 (5)	0.0023 (5)	0.0039 (5)
C8	0.0152 (6)	0.0202 (6)	0.0231 (6)	0.0063 (4)	0.0019 (4)	0.0067 (5)
C9	0.0221 (6)	0.0196 (6)	0.0233 (6)	0.0060 (5)	0.0032 (5)	0.0054 (5)
C10	0.0179 (6)	0.0199 (6)	0.0172 (5)	0.0044 (5)	0.0019 (4)	0.0039 (5)
C11	0.0189 (6)	0.0190 (6)	0.0172 (5)	0.0043 (4)	0.0011 (4)	0.0042 (5)
C12	0.0205 (6)	0.0210 (6)	0.0188 (6)	0.0066 (5)	0.0020 (5)	0.0049 (5)
C13	0.0183 (6)	0.0245 (6)	0.0181 (6)	0.0055 (5)	0.0016 (5)	0.0031 (5)
C14	0.0216 (6)	0.0233 (6)	0.0209 (6)	0.0033 (5)	0.0043 (5)	0.0071 (5)
C15	0.0237 (6)	0.0208 (6)	0.0234 (6)	0.0049 (5)	0.0033 (5)	0.0079 (5)
C16	0.0204 (6)	0.0203 (6)	0.0197 (6)	0.0064 (5)	0.0028 (5)	0.0039 (5)
C17	0.0187 (6)	0.0178 (5)	0.0197 (6)	0.0027 (4)	0.0024 (5)	0.0052 (5)
C18	0.0220 (6)	0.0212 (6)	0.0239 (6)	0.0068 (5)	0.0053 (5)	0.0059 (5)
C19	0.0275 (7)	0.0313 (7)	0.0270 (7)	0.0157 (6)	0.0066 (5)	0.0100 (6)
C20	0.0156 (6)	0.0194 (6)	0.0293 (6)	0.0037 (5)	−0.0002 (5)	0.0021 (5)
C21	0.0157 (6)	0.0177 (6)	0.0253 (6)	0.0045 (4)	0.0010 (5)	0.0043 (5)
C22	0.0180 (6)	0.0208 (6)	0.0213 (6)	0.0045 (5)	−0.0004 (5)	0.0009 (5)
C23	0.0217 (6)	0.0276 (7)	0.0254 (7)	0.0092 (5)	−0.0026 (5)	0.0006 (5)
C24	0.0169 (6)	0.0217 (6)	0.0229 (6)	0.0023 (5)	0.0014 (5)	0.0033 (5)
C25	0.0312 (7)	0.0335 (7)	0.0228 (6)	0.0102 (6)	0.0032 (5)	0.0071 (6)
C26	0.0229 (6)	0.0212 (6)	0.0248 (6)	0.0066 (5)	0.0012 (5)	0.0070 (5)
C27	0.0156 (6)	0.0200 (6)	0.0235 (6)	0.0060 (4)	0.0025 (5)	0.0060 (5)
C28	0.0248 (6)	0.0213 (6)	0.0262 (6)	0.0070 (5)	0.0052 (5)	0.0075 (5)
C29	0.0201 (6)	0.0196 (6)	0.0177 (5)	0.0074 (5)	0.0016 (4)	0.0048 (5)
C30	0.0214 (6)	0.0189 (6)	0.0170 (5)	0.0069 (5)	−0.0001 (5)	0.0028 (5)
C31	0.0215 (6)	0.0197 (6)	0.0213 (6)	0.0056 (5)	0.0025 (5)	0.0042 (5)
C32	0.0210 (6)	0.0261 (6)	0.0178 (6)	0.0091 (5)	0.0030 (5)	0.0044 (5)
C33	0.0274 (7)	0.0218 (6)	0.0205 (6)	0.0122 (5)	0.0006 (5)	0.0019 (5)
C34	0.0254 (6)	0.0191 (6)	0.0207 (6)	0.0078 (5)	0.0009 (5)	0.0044 (5)
C35	0.0206 (6)	0.0210 (6)	0.0178 (5)	0.0063 (5)	0.0013 (5)	0.0041 (5)
C36	0.0225 (6)	0.0180 (6)	0.0186 (6)	0.0068 (5)	0.0005 (5)	0.0035 (5)
C37	0.0228 (6)	0.0214 (6)	0.0245 (6)	0.0076 (5)	0.0052 (5)	0.0064 (5)
C38	0.0247 (7)	0.0311 (7)	0.0330 (7)	0.0062 (6)	0.0092 (6)	0.0067 (6)

Geometric parameters (Å, º)

O1—C1	1.3972 (15)	C15—H15	0.9500
O1—C4	1.3987 (16)	C17—C18	1.4811 (16)
O2—C1	1.1991 (15)	C18—H18A	0.9800
O3—C4	1.1983 (16)	C18—H18B	0.9800
O4—C17	1.3805 (14)	C18—H18C	0.9800
O4—C16	1.3853 (14)	C19—H19A	0.9800
O5—C13	1.3727 (14)	C19—H19B	0.9800
O5—C19	1.4268 (15)	C19—H19C	0.9800
O6—C20	1.3949 (16)	C20—C21	1.4789 (17)
O6—C23	1.3973 (16)	C21—C27	1.3614 (17)
O7—C20	1.2008 (16)	C21—C22	1.4800 (17)
O8—C23	1.2009 (16)	C22—C24	1.3564 (18)
O9—C35	1.3829 (14)	C22—C23	1.4836 (17)
O9—C36	1.3858 (14)	C24—C26	1.4970 (17)
O10—C32	1.3774 (15)	C24—C25	1.5038 (17)
O10—C38	1.4256 (16)	C24—C36	3.5403 (17)
C1—C2	1.4763 (16)	C25—H25A	0.9800
C2—C8	1.3592 (17)	C25—H25B	0.9800
C2—C3	1.4768 (17)	C25—H25C	0.9800
C3—C5	1.3554 (18)	C26—H26A	0.9800
C3—C4	1.4790 (17)	C26—H26B	0.9800
C5—C7	1.4982 (17)	C26—H26C	0.9800
C5—C6	1.5024 (17)	C27—C29	1.4686 (16)
C5—C17	3.6629 (17)	C27—C28	1.5119 (17)
C6—H6A	0.9800	C28—H28A	0.9800
C6—H6B	0.9800	C28—H28B	0.9800
C6—H6C	0.9800	C28—H28C	0.9800
C7—H7A	0.9800	C29—C36	1.3632 (17)
C7—H7B	0.9800	C29—C30	1.4497 (16)
C7—H7C	0.9800	C30—C35	1.3875 (17)
C8—C10	1.4669 (16)	C30—C31	1.4024 (17)
C8—C9	1.5122 (17)	C31—C32	1.3881 (17)
C9—H9A	0.9800	C31—H31	0.9500
C9—H9B	0.9800	C32—C33	1.4055 (18)
C9—H9C	0.9800	C33—C34	1.3829 (18)
C10—C17	1.3654 (17)	C33—H33	0.9500
C10—C11	1.4534 (16)	C34—C35	1.3890 (17)
C11—C16	1.3901 (17)	C34—H34	0.9500
C11—C12	1.4010 (16)	C36—C37	1.4774 (16)
C12—C13	1.3869 (17)	C37—H37A	0.9800
C12—H12	0.9500	C37—H37B	0.9800
C13—C14	1.4072 (18)	C37—H37C	0.9800
C14—C15	1.3850 (18)	C38—H38A	0.9800
C14—H14	0.9500	C38—H38B	0.9800
C15—C16	1.3862 (17)	C38—H38C	0.9800
C1—O1—C4	110.42 (9)	O5—C19—H19C	109.5
C17—O4—C16	106.12 (9)	H19A—C19—H19C	109.5
C13—O5—C19	116.75 (9)	H19B—C19—H19C	109.5
C20—O6—C23	110.26 (9)	O7—C20—O6	118.97 (11)
C35—O9—C36	106.03 (9)	O7—C20—C21	132.16 (12)
C32—O10—C38	116.90 (10)	O6—C20—C21	108.73 (10)
O2—C1—O1	118.97 (11)	C27—C21—C20	120.29 (11)
O2—C1—C2	132.87 (12)	C27—C21—C22	133.53 (11)
O1—C1—C2	108.09 (10)	C20—C21—C22	105.65 (10)
C8—C2—C1	121.62 (11)	C24—C22—C21	130.98 (11)
C8—C2—C3	132.19 (11)	C24—C22—C23	122.02 (11)
C1—C2—C3	105.69 (10)	C21—C22—C23	105.27 (10)
C5—C3—C2	129.69 (11)	O8—C23—O6	118.50 (12)
C5—C3—C4	122.85 (11)	O8—C23—C22	133.05 (13)
C2—C3—C4	105.08 (10)	O6—C23—C22	108.41 (10)
O3—C4—O1	118.97 (12)	C22—C24—C26	123.43 (11)
O3—C4—C3	133.00 (13)	C22—C24—C25	123.25 (11)
O1—C4—C3	108.02 (10)	C26—C24—C25	113.27 (11)
C3—C5—C7	121.93 (11)	C24—C25—H25A	109.5
C3—C5—C6	123.77 (11)	C24—C25—H25B	109.5
C7—C5—C6	114.22 (11)	H25A—C25—H25B	109.5
C5—C6—H6A	109.5	C24—C25—H25C	109.5
C5—C6—H6B	109.5	H25A—C25—H25C	109.5
H6A—C6—H6B	109.5	H25B—C25—H25C	109.5
C5—C6—H6C	109.5	C24—C26—H26A	109.5
H6A—C6—H6C	109.5	C24—C26—H26B	109.5
H6B—C6—H6C	109.5	H26A—C26—H26B	109.5
C5—C7—H7A	109.5	C24—C26—H26C	109.5
C5—C7—H7B	109.5	H26A—C26—H26C	109.5
H7A—C7—H7B	109.5	H26B—C26—H26C	109.5
C5—C7—H7C	109.5	C21—C27—C29	122.25 (11)
H7A—C7—H7C	109.5	C21—C27—C28	122.29 (11)
H7B—C7—H7C	109.5	C29—C27—C28	115.41 (10)
C2—C8—C10	121.83 (11)	C27—C28—H28A	109.5
C2—C8—C9	122.35 (11)	C27—C28—H28B	109.5
C10—C8—C9	115.56 (10)	H28A—C28—H28B	109.5
C8—C9—H9A	109.5	C27—C28—H28C	109.5
C8—C9—H9B	109.5	H28A—C28—H28C	109.5
H9A—C9—H9B	109.5	H28B—C28—H28C	109.5
C8—C9—H9C	109.5	C36—C29—C30	106.59 (10)
H9A—C9—H9C	109.5	C36—C29—C27	126.72 (11)
H9B—C9—H9C	109.5	C30—C29—C27	126.69 (11)
C17—C10—C11	106.31 (10)	C35—C30—C31	119.89 (11)
C17—C10—C8	124.95 (11)	C35—C30—C29	105.56 (10)
C11—C10—C8	128.23 (11)	C31—C30—C29	134.40 (11)
C16—C11—C12	119.84 (11)	C32—C31—C30	117.25 (11)
C16—C11—C10	105.59 (10)	C32—C31—H31	121.4
C12—C11—C10	134.45 (11)	C30—C31—H31	121.4
C13—C12—C11	117.45 (11)	O10—C32—C31	123.83 (11)
C13—C12—H12	121.3	O10—C32—C33	114.46 (11)
C11—C12—H12	121.3	C31—C32—C33	121.69 (11)
O5—C13—C12	123.86 (11)	C34—C33—C32	121.34 (11)
O5—C13—C14	114.50 (10)	C34—C33—H33	119.3
C12—C13—C14	121.64 (11)	C32—C33—H33	119.3
C15—C14—C13	121.09 (11)	C33—C34—C35	116.29 (11)
C15—C14—H14	119.5	C33—C34—H34	121.9
C13—C14—H14	119.5	C35—C34—H34	121.9
C14—C15—C16	116.59 (11)	O9—C35—C30	110.65 (10)
C14—C15—H15	121.7	O9—C35—C34	125.79 (11)
C16—C15—H15	121.7	C30—C35—C34	123.52 (11)
O4—C16—C15	126.11 (11)	C29—C36—O9	111.11 (10)
O4—C16—C11	110.54 (10)	C29—C36—C37	133.34 (11)
C15—C16—C11	123.34 (11)	O9—C36—C37	115.53 (10)
C10—C17—O4	111.44 (10)	C36—C37—H37A	109.5
C10—C17—C18	132.88 (11)	C36—C37—H37B	109.5
O4—C17—C18	115.58 (10)	H37A—C37—H37B	109.5
C17—C18—H18A	109.5	C36—C37—H37C	109.5
C17—C18—H18B	109.5	H37A—C37—H37C	109.5
H18A—C18—H18B	109.5	H37B—C37—H37C	109.5
C17—C18—H18C	109.5	O10—C38—H38A	109.5
H18A—C18—H18C	109.5	O10—C38—H38B	109.5
H18B—C18—H18C	109.5	H38A—C38—H38B	109.5
O5—C19—H19A	109.5	O10—C38—H38C	109.5
O5—C19—H19B	109.5	H38A—C38—H38C	109.5
H19A—C19—H19B	109.5	H38B—C38—H38C	109.5
C2—C8—C10—C17	52.48 (18)	C21—C27—C29—C36	51.58 (19)
C3—C2—C8—C10	14.7 (2)	C22—C21—C27—C29	9.0 (2)
C8—C2—C3—C5	41.9 (2)	C27—C21—C22—C24	36.3 (2)
C2—C8—C10—C11	−136.83 (13)	C21—C27—C29—C30	−129.36 (13)
C1—C2—C3—C5	−146.29 (13)	C20—C21—C22—C24	−152.36 (13)

(III-Z) 3-isopropylidene-4-[(Z)-1-(5-methoxy-2-methyl-1-benzofuran-3- yl)ethylidene]tetrahydrofuran-2,5-dione

Crystal data

C19H18O5	F(000) = 1376
Mr = 326.33	Dx = 1.370 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 31599 reflections
a = 26.5923 (4) Å	θ = 2.9–27.5°
b = 8.6140 (1) Å	µ = 0.10 mm^−1
c = 15.3550 (2) Å	T = 100 K
β = 115.8482 (8)°	Fragment, colourless
V = 3165.41 (7) Å^3	0.30 × 0.25 × 0.10 mm
Z = 8

Data collection

KappaCCD diffractometer	3606 independent reflections
Radiation source: fine-focus sealed tube	3205 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.033
CCD scans	θmax = 27.5°, θmin = 3.0°
Absorption correction: multi-scan (DENZO and SCALEPACK; Otwinowski & Minor, 1997)	h = −33→34
Tmin = 0.971, Tmax = 0.990	k = −11→11
54136 measured reflections	l = −19→19

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.034	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.091	H-atom parameters constrained
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0494P)^2 + 1.6756P] where P = (Fo^2 + 2Fc^2)/3
3606 reflections	(Δ/σ)max < 0.001
222 parameters	Δρmax = 0.25 e Å^−3
0 restraints	Δρmin = −0.22 e Å^−3

Special details

Experimental. General preparation of fulgides (I)–(III): a solution of diethyl isopropylidene succinate (15 mmol) in THF [tetrahydrofuran?] (15 ml) was cooled to 195 K and LDA (7.5 ml, 15 mmol; 2 M, THF/n-heptane/ethylbenzene) was added under an argon atmosphere. After stirring for 1 h the appropriate ketone (10 mmol) dissolved in THF (30 ml) was added via a syringe. The reaction mixture was allowed to warm to room temperature overnight and stirred for an additional 24 h. The reaction progress was monitored by TLC [thin layer chromatography?]. Afterwards the reaction mixture was acidified with aqueous HCl (2 M) and the aqueous layer was extracted with ethyl acetate (3 x 50 ml). The combined organic layers were washed with saturated aqueous NaCl solution, dried over MgSO₄ and the solvent was removed in vacuo. The residue was dissolved in cyclohexane/ethyl acetate (7:3), filtered over silica gel and the solvent removed in vacuo again. The residue was dissolved in ethanol (60 ml) and a saturated aqueous solution of KOH (5 ml) was added. After stirring for 20 h at 343 K the reaction mixture was poured onto ice and acidified with aqueous HCl (2 M). The aqueous layer was extracted with ethyl acetate (3 x 50 ml) and the combined organic layers were washed with saturated aqueous NaCl, dried over MgSO₄ and the solvent was removed in vacuo. The dark brown residue was dissolved in dichloromethane (50 ml) and N,N'-dicyclohexylcarbodiimide (4.13 g, 20 mmol) was added. After stirring for 48 h the reaction mixture was filtered over silica gel and the solvent was removed in vacuo. The products were purified by column chromatography and recrystallized from adapted solvents.

(III-Z): ield 10% (recrystallized from ethanol); R_f=0.11 (cyclohexane/ethyl acetate 9:1); ¹H NMR (500 MHz, CDCl₃, 25 °C, CDCl₃=7.24 p.p.m.) δ=2.04 (s, 3H; CH₃), 2.28 (s, 3H, CH₃), 2.36 (s, 3H, CH₃), 2.46 (s, 3H, CH₃), 3.80 (s, 3H, CH₃), 6.83 (m, 2H, Ar—H), 7.31 p.p.m. (d, ³J(H,H)=8.8 Hz, 1H, Ar—H); ¹³C NMR (126 MHz, CDCl₃, 25 °C, CDCl₃=77.0 p.p.m.) δ=13.6, 22.4, 24.0, 27.2, 66.0, 103.0, 111.6, 111.7, 114.9, 121.3, 122.8, 127.6, 143.8, 148.9, 154.3, 156.0, 157.2, 160.9, 163.2 p.p.m.; MS (70 eV): m/z (%): 327 (21), 326 (100) [M⁺], 311 (37) [M - CH₃⁺], 309 (11), 283 (18), 281 (10), 267 (67), 265 (12), 253 (12) 239 (20), 227 (15), 204 (10), 162 (19), 152 (10), 115 (10); HRMS (m/z) [M⁺] calcd for C₁₉H₁₈O₅: 326.11542; found 326.11390.

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
O1	0.43332 (3)	0.28489 (9)	0.50657 (5)	0.02243 (18)
O2	0.36292 (3)	0.28865 (9)	0.54967 (5)	0.02397 (18)
O3	0.49219 (3)	0.32877 (9)	0.43999 (6)	0.02698 (19)
O4	0.25671 (3)	0.56512 (8)	0.58670 (5)	0.01936 (17)
O5	0.41157 (3)	0.96371 (9)	0.84152 (5)	0.02463 (18)
C1	0.38619 (4)	0.35342 (12)	0.50851 (7)	0.0191 (2)
C2	0.37786 (4)	0.50603 (12)	0.45912 (7)	0.0168 (2)
C3	0.41158 (4)	0.49955 (12)	0.40447 (7)	0.0176 (2)
C4	0.45132 (4)	0.37032 (12)	0.44801 (7)	0.0208 (2)
C5	0.40443 (4)	0.57194 (12)	0.32176 (7)	0.0183 (2)
C6	0.44539 (4)	0.55653 (13)	0.27886 (8)	0.0235 (2)
H6A	0.4339	0.6241	0.2221	0.035*	0.50
H6B	0.4462	0.4485	0.2595	0.035*	0.50
H6C	0.4827	0.5870	0.3271	0.035*	0.50
H6D	0.4747	0.4823	0.3170	0.035*	0.50
H6E	0.4623	0.6579	0.2796	0.035*	0.50
H6F	0.4259	0.5194	0.2120	0.035*	0.50
C7	0.35396 (4)	0.66927 (12)	0.26469 (7)	0.0202 (2)
H7A	0.3244	0.6448	0.2844	0.030*
H7B	0.3407	0.6473	0.1956	0.030*
H7C	0.3638	0.7794	0.2768	0.030*
C8	0.35857 (4)	0.63356 (12)	0.48736 (7)	0.0168 (2)
C9	0.37121 (4)	0.79532 (11)	0.46521 (7)	0.0193 (2)
H9A	0.4053	0.7938	0.4556	0.029*
H9B	0.3766	0.8643	0.5194	0.029*
H9C	0.3400	0.8332	0.4063	0.029*
C10	0.32634 (4)	0.62310 (11)	0.54440 (7)	0.0170 (2)
C11	0.33636 (4)	0.70789 (11)	0.63227 (7)	0.0175 (2)
C12	0.37859 (4)	0.80759 (11)	0.69452 (7)	0.0187 (2)
H12	0.4094	0.8348	0.6819	0.022*
C13	0.37377 (4)	0.86504 (12)	0.77526 (7)	0.0201 (2)
C14	0.32842 (4)	0.82390 (12)	0.79484 (7)	0.0217 (2)
H14	0.3259	0.8665	0.8498	0.026*
C15	0.28751 (4)	0.72235 (12)	0.73519 (7)	0.0209 (2)
H15	0.2573	0.6921	0.7488	0.025*
C16	0.29269 (4)	0.66695 (12)	0.65469 (7)	0.0184 (2)
C17	0.27817 (4)	0.54146 (12)	0.52062 (7)	0.0181 (2)
C18	0.24448 (4)	0.44074 (12)	0.43702 (7)	0.0211 (2)
H18A	0.2461	0.4811	0.3786	0.032*
H18B	0.2056	0.4397	0.4276	0.032*
H18C	0.2595	0.3349	0.4496	0.032*
C19	0.46033 (5)	1.00277 (14)	0.82939 (9)	0.0290 (3)
H19A	0.4809	0.9078	0.8303	0.043*
H19B	0.4843	1.0713	0.8822	0.043*
H19C	0.4493	1.0560	0.7673	0.043*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0220 (4)	0.0213 (4)	0.0212 (4)	0.0046 (3)	0.0069 (3)	−0.0002 (3)
O2	0.0323 (4)	0.0203 (4)	0.0217 (4)	0.0005 (3)	0.0140 (3)	0.0022 (3)
O3	0.0166 (4)	0.0285 (4)	0.0335 (4)	0.0011 (3)	0.0087 (3)	−0.0097 (3)
O4	0.0185 (3)	0.0228 (4)	0.0189 (3)	0.0012 (3)	0.0101 (3)	0.0022 (3)
O5	0.0306 (4)	0.0219 (4)	0.0203 (4)	0.0003 (3)	0.0101 (3)	−0.0036 (3)
C1	0.0207 (5)	0.0188 (5)	0.0158 (4)	0.0012 (4)	0.0060 (4)	−0.0025 (4)
C2	0.0157 (4)	0.0190 (5)	0.0147 (4)	−0.0014 (4)	0.0057 (4)	−0.0009 (3)
C3	0.0147 (4)	0.0192 (5)	0.0186 (5)	−0.0014 (4)	0.0071 (4)	−0.0047 (4)
C4	0.0171 (5)	0.0224 (5)	0.0196 (5)	−0.0017 (4)	0.0050 (4)	−0.0068 (4)
C5	0.0172 (5)	0.0197 (5)	0.0193 (5)	−0.0048 (4)	0.0092 (4)	−0.0059 (4)
C6	0.0218 (5)	0.0292 (6)	0.0243 (5)	−0.0038 (4)	0.0147 (4)	−0.0048 (4)
C7	0.0211 (5)	0.0219 (5)	0.0185 (5)	−0.0016 (4)	0.0096 (4)	−0.0006 (4)
C8	0.0158 (4)	0.0196 (5)	0.0147 (4)	0.0002 (4)	0.0063 (4)	0.0006 (4)
C9	0.0232 (5)	0.0177 (5)	0.0202 (5)	−0.0007 (4)	0.0123 (4)	−0.0006 (4)
C10	0.0196 (5)	0.0163 (5)	0.0164 (4)	0.0024 (4)	0.0088 (4)	0.0016 (3)
C11	0.0201 (5)	0.0172 (5)	0.0169 (4)	0.0048 (4)	0.0096 (4)	0.0032 (4)
C12	0.0210 (5)	0.0179 (5)	0.0187 (5)	0.0024 (4)	0.0100 (4)	0.0016 (4)
C13	0.0244 (5)	0.0166 (5)	0.0175 (4)	0.0050 (4)	0.0074 (4)	0.0015 (4)
C14	0.0282 (5)	0.0225 (5)	0.0166 (5)	0.0096 (4)	0.0118 (4)	0.0036 (4)
C15	0.0220 (5)	0.0243 (5)	0.0199 (5)	0.0077 (4)	0.0124 (4)	0.0062 (4)
C16	0.0187 (5)	0.0189 (5)	0.0177 (5)	0.0037 (4)	0.0081 (4)	0.0037 (4)
C17	0.0199 (5)	0.0187 (5)	0.0170 (4)	0.0034 (4)	0.0092 (4)	0.0040 (4)
C18	0.0219 (5)	0.0208 (5)	0.0197 (5)	−0.0011 (4)	0.0080 (4)	0.0020 (4)
C19	0.0326 (6)	0.0238 (6)	0.0284 (6)	−0.0048 (5)	0.0113 (5)	−0.0028 (4)

Geometric parameters (Å, º)

O1—C1	1.3974 (12)	C7—H7C	0.9800
O1—C4	1.3979 (13)	C8—C10	1.4712 (13)
O2—C1	1.1977 (13)	C8—C9	1.5066 (13)
O3—C4	1.2006 (13)	C9—H9A	0.9800
O4—C17	1.3791 (12)	C9—H9B	0.9800
O4—C16	1.3797 (12)	C9—H9C	0.9800
O5—C13	1.3698 (13)	C10—C17	1.3641 (14)
O5—C19	1.4282 (14)	C10—C11	1.4530 (13)
C1—C2	1.4853 (14)	C11—C16	1.3929 (14)
C2—C8	1.3609 (14)	C11—C12	1.4059 (14)
C2—C3	1.4722 (13)	C12—C13	1.3918 (14)
C3—C5	1.3517 (14)	C12—H12	0.9500
C3—C4	1.4788 (14)	C13—C14	1.4093 (15)
C5—C7	1.4989 (14)	C14—C15	1.3852 (16)
C5—C6	1.5047 (13)	C14—H14	0.9500
C5—C17	5.4409 (14)	C15—C16	1.3868 (14)
C6—H6A	0.9800	C15—H15	0.9500
C6—H6B	0.9800	C17—C18	1.4835 (14)
C6—H6C	0.9800	C18—H18A	0.9800
C6—H6D	0.9800	C18—H18B	0.9800
C6—H6E	0.9800	C18—H18C	0.9800
C6—H6F	0.9800	C19—H19A	0.9800
C7—H7A	0.9800	C19—H19B	0.9800
C7—H7B	0.9800	C19—H19C	0.9800
C1—O1—C4	110.68 (8)	C2—C8—C10	122.59 (9)
C17—O4—C16	106.13 (8)	C2—C8—C9	121.50 (9)
C13—O5—C19	117.60 (8)	C10—C8—C9	115.86 (8)
O2—C1—O1	119.28 (9)	C8—C9—H9A	109.5
O2—C1—C2	133.27 (9)	C8—C9—H9B	109.5
O1—C1—C2	107.36 (8)	H9A—C9—H9B	109.5
C8—C2—C3	128.33 (9)	C8—C9—H9C	109.5
C8—C2—C1	123.01 (9)	H9A—C9—H9C	109.5
C3—C2—C1	105.38 (8)	H9B—C9—H9C	109.5
C5—C3—C2	130.30 (9)	C17—C10—C11	106.16 (8)
C5—C3—C4	123.51 (9)	C17—C10—C8	126.51 (9)
C2—C3—C4	105.29 (8)	C11—C10—C8	127.12 (9)
O3—C4—O1	119.22 (10)	C16—C11—C12	119.44 (9)
O3—C4—C3	132.73 (10)	C16—C11—C10	105.50 (9)
O1—C4—C3	108.03 (8)	C12—C11—C10	135.00 (9)
C3—C5—C7	122.05 (9)	C13—C12—C11	117.79 (9)
C3—C5—C6	122.58 (9)	C13—C12—H12	121.1
C7—C5—C6	115.34 (9)	C11—C12—H12	121.1
C5—C6—H6A	109.5	O5—C13—C12	124.02 (10)
C5—C6—H6B	109.5	O5—C13—C14	114.63 (9)
H6A—C6—H6B	109.5	C12—C13—C14	121.36 (10)
C5—C6—H6C	109.5	C15—C14—C13	121.08 (9)
H6A—C6—H6C	109.5	C15—C14—H14	119.5
H6B—C6—H6C	109.5	C13—C14—H14	119.5
C5—C6—H6D	109.5	C14—C15—C16	116.87 (9)
H6A—C6—H6D	141.1	C14—C15—H15	121.6
H6B—C6—H6D	56.3	C16—C15—H15	121.6
H6C—C6—H6D	56.3	O4—C16—C15	125.99 (9)
C5—C6—H6E	109.5	O4—C16—C11	110.59 (8)
H6A—C6—H6E	56.3	C15—C16—C11	123.42 (10)
H6B—C6—H6E	141.1	C10—C17—O4	111.62 (9)
H6C—C6—H6E	56.3	C10—C17—C18	132.50 (9)
H6D—C6—H6E	109.5	O4—C17—C18	115.82 (9)
C5—C6—H6F	109.5	C17—C18—H18A	109.5
H6A—C6—H6F	56.3	C17—C18—H18B	109.5
H6B—C6—H6F	56.3	H18A—C18—H18B	109.5
H6C—C6—H6F	141.1	C17—C18—H18C	109.5
H6D—C6—H6F	109.5	H18A—C18—H18C	109.5
H6E—C6—H6F	109.5	H18B—C18—H18C	109.5
C5—C7—H7A	109.5	O5—C19—H19A	109.5
C5—C7—H7B	109.5	O5—C19—H19B	109.5
H7A—C7—H7B	109.5	H19A—C19—H19B	109.5
C5—C7—H7C	109.5	O5—C19—H19C	109.5
H7A—C7—H7C	109.5	H19A—C19—H19C	109.5
H7B—C7—H7C	109.5	H19B—C19—H19C	109.5
C2—C8—C10—C17	−55.72 (15)	C2—C8—C10—C11	130.31 (11)
C3—C2—C8—C10	−178.29 (9)	C1—C2—C3—C5	151.31 (10)
C8—C2—C3—C5	−49.02 (16)